Have a Harmon kardon avr 225 with infinity speakers. Recently, I noticed a buzzing out of my front right speaker at very low volumes. The Buzzing is virtually gone at normal volumes and above. I switched the front speakers and the buzzing stayed in the same location, so I believe it is a problem with the receiver. The buzzing is loudest at the lowest volume and gradually get softer as I increase the volume. Totally gone if I mute or unplug the input. Input is a optical cable.

Have a Harmon kardon avr 225 with infinity speakers. Recently, I noticed a buzzing out of my front right speaker at very low volumes. The Buzzing is virtually gone at normal volumes and above. I switched the front speakers and the buzzing stayed in the same location, so I believe it is a problem with the receiver. The buzzing is loudest at the lowest volume and gradually get softer as I increase the volume. Totally gone if I mute or unplug the input. Input is a optical cable.

Impossible to diagnose at a distamce, I am afraid, but it does sound as if something in the D/A section of your receiver has failed. Have you added any other sources? Do you get the buzzing if you switch to other inputs?

I first swopped the speakers around to determine if I might have unknowingly damaged them. Thereafter I swopped the speaker cables althought after speaking to the local dealer realised was unnecessary, that's a component which doesn't trip often esp with banana plugs.

When it doubt I think an additional source always helps with troubleshooting as John mentioned. I finally used a standard audio cable to hook up my iPod realised it was the amplifier.